A global computer network (e.g., the Internet) provides a marketplace for advertisers based on keywords. More specifically, an end user commonly uses a search engine to browse for content on the global computer network or browses content including articles and emails that contain keywords or keyword sets. Typically the search engine operates on keywords entered by the end user as search terms or encountered in content viewed by the user. In cooperation, an ad engine provides, from a depository of advertisements, ads targeted for the same keywords as those used by the search engine on the content in response to the end user's search query. The provided corresponding targeted ads of the ad engine are displayed to the end user along with the search results (content) of the search engine. Ads are displayed in many forms including lists of textual ads, banners, pop up windows and sponsor or other columns.
Thus ad delivery services, ad engines and depositories typically charge per search term or keyword that a subject ad is targeted for. For example, the advertisement rate may be                83¢ for a given ad to be selected and displayed in a top (first) grouping based on the search term “Vegas”;        $2.00 for the given ad to be similarly selected and displayed based on the search term “hotels” and        $4.50 for the given ad to be selected and displayed based on the search term “Vegas hotels”.These rates are often set by a persistent auction, allowing advertisers to bid for placement adjacent a keyword or keyword set against other advertisers seeking similar placement. This keyword bidding creates a marketplace around the keyword or keyword set, setting the price for this advertising dynamically for each keyword or keyword set. Further, the ad owner pays these rates (or the accumulation thereof) for an end user clicking on (selecting) the ad as displayed. Thus a “cost per click” accounting is common in the industry.        
There are other cost structures for advertising on the Internet, for example cost per acquisition or cost per 1000 impressions (“views”). Generally the greater visibility (e.g. pop up ads, top of page banners, first item on a sponsor list displayed next to search results, etc.) the higher the price for the ad.